" I said to Qatada: Did you hear it from Anas? He replied in the affir- mative and added: We had inquired of him about it."
Sahih Muslim Book 4, Hadith 53
← Previous Hadith I observed prayer along with the Messenger of Allah (ﷺ) and with Abu Bakr, Umar and Uthman (may Allah be pleased with all of them), but I never heard any one of them reciting Bismillah-ir-Rahman-ir-Rahim loudly.

Sahih Muslim Book 4, Hadith 52 Next Hadith → 'Umar b. al-Khattab used to recite loudly these words: Subhanak Allahumma wa bi hamdika wa tabarakasmuka wa ta'ala jadduka wa la ilaha ghairuka and did not recite Bismillah ir- Rahman-ir-Rahim (loudly) at the beginning of the recitation or at the end of it.

Sahih Muslim Book 4, Hadith 54